Hypnotic spellbinder

Hypnosis is nothing if not magic. That is both its allure and its problem. It attracts many people of mystical inclinations, who recognise it as the kind of shamanistic ritual that has been used to enter the spirit world since time immemorial. It's also enduringly popular as a form of stage conjuring in which people volunteer to make public spectacles of themselves. But its hold on the public imagination, as firm as ever after 200 years, has helped to deny it the medical credibility its advocates have always craved. Robin Waterfield wants hypnosis to have it all. He spends a lot of time slaying canards, such as Cold War fantasies of assassins programmed by hypnotic suggestion. Hypnosis is not a sinister tool for manipulative Svengalis, but a "gentle, effective and empowering therapy". At the same time, though, he believes it is a means to tap into extraordinary capacities that are hidden in the depths of the mind. Its advocates aren't inspired by it because it offers an alternative to drugs for pain relief - though that, for Waterfield, is its chief selling point - but because they believe "the world is not dull, but is infused with magic".

To reach the depths, a person must enter into a contract based, as Waterfield nicely puts it, on "inequality of will". The hypnotist's will must be stronger than that of the subject, who enters a relaxed state in which he or she is more than usually amenable to suggestions. The dominant view among scientific researchers, he admits, is that this is all it is. The magic is only stage ritual, plus the placebo effect. Waterfield hopes, however, to convince his readers that it's not just a state of mind, but a bona fide altered state of consciousness.

He will have difficulty pleasing the different strands of opinion among them. Many of his natural sympathisers may be alienated by his opinion that the New Age is giving hypnosis a bad name. Sceptics are not likely to be persuaded by a case which he admits is one-sided, omitting the doubters' arguments because they "are too many, and too scientifically sophisticated". Nor does he give either side any real data to go on. Although sceptics and enthusiasts may wrangle endlessly over whether hypnosis is a distinct state of consciousness, many in both camps would agree that the bottom line is whether it works. The main objection to using hypnosis in medical treatment is that it is unreliable. Waterfield assures us that it is "less erratic than commonly supposed", but doesn't give us any figures indicating how erratic it may be.

Suspicions about hypnosis centre on the potential for abuse that comes with inequality of will. Here Hidden Depths stumbles on its dogged path through the middle ground. Hypnosis, we are repeatedly assured, does not cause people to behave counter to deeply held moral codes. Throughout its history, though, it has given rise to accusations of rape. Therefore, Waterfield concludes, these complaints must have been made by women with loose morals who wanted it really. His discussion is muddled - on one page he calls it rape, on the next he suggests that it is not - and rather shabby.

This is not the only part of Hidden Depths that contains contradictions, for the book is a coalition of attitudes. The sensible faction has the upper hand for much of the time, denouncing the confabulation of false memories or dismissing claims that the dead can speak through the hypnotised living. But, while in one paragraph Waterfield voices his doubt that individuals survive after death, in the preceding one he casually describes how he once killed a bluebottle using only his mind. The fly annoys him; it drops dead: magical thinking in a nutshell.

And this is what he means, deep down, when he talks about extraordinary powers. The respectable pitch for hypnosis is that it allows people to exercise control over their bodies in ways that seem extraordinary, making warts or pain disappear. But hypnosis wouldn't cast a spell if people didn't believe that there was real magic at the bottom of it.